Depends on what he means. He could just mean that he made extra efforts to make sure that his candidate pool for the job wasn't just men.

He could also mean that in a tie for qualifications (between a man and a woman), he would hire the woman; which, while possibly illegal to the letter of the law (in the UK, possibly elsewhere), doesn't seem like a horrible thing. He explicitly states that it's to counter-act male-skewed tech work environments, so presumably if the work place were 50/50 men-to-women, he would relax this preference to women (as a tie-breaker).